1. Field of the Invention
The present invention relates generally to medical apparatus. More particularly, the present invention relates to apparatus for treating ureters and other body lumens.
It is common for kidney stones to pass from the kidney through the ureter to the urinary bladder. While muscular peristalsis of the ureter will often pass the stones into the bladder without complication, in some instances large and/or irregularly shaped stones may become lodged within the ureter causing discomfort and potential damage to the ureter and upper collective system.
A number of ways have been proposed for dislodging such kidney stones. For example, extracorporeal shock wave lithotripsy (ESWL) can be used to break up the kidney stones but is often ineffective when the stones are present in the ureter. Moreover, ESWL can produce irregularly-shaped fragments which, while smaller than the original stone, may have sharp edges that will prevent spontaneous passage of the particles through the ureter. In the case of a stone or fragment impacted in the ureter, it is common practice to attempt capture, using a wire stone basket. The basket is introduced through a ureteroscope which itself is typically introduced retrograde through the urinary tract.
In many cases, further lithotripsy through the scope is performed (ISWL). It is often difficult to advance such stone baskets past the obstructing material. Attempts to pass wire baskets or other grasping apparatus past a stone lodged in the ureter also presents risk of damage to the ureter. Abrasion, stretching, or perforation of the ureter at the impaction site can cause local urine leakage or edema even if the stone or resulting debris is successfully captured; and removal of the basket with the stone may be quite difficult. In some instances, baskets containing captured stones or fragments cannot themselves be removed, and it is difficult if not impossible to release the captured stone material back into the lumen of the ureter. In those cases, the basket must often be retrieved surgically. Finally, if and/or when ISWL is performed, it would be useful to have some means of stabilizing stone fragments at the treatment site, rather than letting them escape up the ureter in a retrograde direction.
As an improvement over lithotripsy and the use of baskets for collecting kidney stones and debris, it has recently been proposed to use a compacted length of material to form an occluding structure within a ureter. The compacted length of material can be used to either directly draw and remove the kidney stone from the ureter into the bladder. Alternatively, the compacted length of material can be used to contain fragments which are produced in an energy-based lithotripsy procedure. As described in prior copending application Ser. No. 10/866,866, the length of material can be an everting tubular member, a flat membrane which folds as an accordion structure, can or take a variety of other configurations. None of the prior described occlusion structures, however, has been optimum in all respects.
For these reasons it would be desirable to provide improved apparatus for deploying and compacting a length of material in order to occlude a body lumen, such as a ureter, when performing procedures for the removal and/or lithotripsy of kidney stones. In particular, it would be desirable to provide apparatus having material lengths which may be delivered in a very low profile configuration while permitting deployment into a relatively high volume configuration having a substantial density and ability to conform to symmetric and non-symmetric body lumens to help assure effective occlusion of the body lumen, particularly occlusion of ureters to prevent the passage of kidney stones and kidney stone fragments. The apparatus should also be atraumatic in use, require significantly less skill than basket manipulation, optionally allow the release of captured material, should be simple and economical in construction and use, and should provide minimum risk and trauma to the patient. At least some of these objectives will be met by the inventions described hereinbelow.
2. Description of the Background Art
The use of an everting sleeve composed of thin, tensilized polytetrafluoroethylene for introducing catheters to body lumens is described in U.S. Pat. Nos. 5,531,717; 5,676,688; 5,711,841; 5,897,535; 6,007,488; 6,240,968; and EP605427B1. A wire basket for preventing stone fragment movement through a body lumen during lithotripsy procedure is available under the Stone Cone tradename from Boston Scientific Corporation. See Published U.S. Application No. 2003/0120281. Copending application Ser. No. 10/794,337, filed on Mar. 5, 2004, the full disclosure of which is incorporated herein by reference, describes a sheet delivery system that could be used in performing some of the methods described herein.